1. As far as the distinction between internal and external differentiation is concerned, the legal conditions for transitional measures have not changed, and a glance back at the practice so far is still of interest. If one is looking at the enlargements of the Communities and the Union so far, certain patterns for accession-related transition regulations can be found. The Commission has worked, from the start of the first accession negotiations, on the assumption that only the conditions of the accession and the alterations made necessary to the Treaty by this accession were negotiable whereas, in principle, the regulations and aims of the Treaties had to be accepted by the new Member States without reservation.15 Heads of states and governments had already emphasized in 1969 that a condition for accession is the adoption of the Community law in force.16
2. It is, therefore, not surprising that the arrangements for transitional measures in accession treaties were, in principle, of temporary character.17 The extent of the adaptation measures thought necessary varied according to the conditions in the accessing states,18 whereby the preparation for the accession itself naturally played an important role, but - as especially demonstrated by the last accession - the extent to which Community regulations already exist and, therefore, have to be taken over did as well.19
a) As to their protective aim, the transitional measures employed for the first accessions (United Kingdom, Denmark and Ireland in 1973) mainly served the new Member States. Those states received the chance to incrementally adapt their national regulations in some sectors to the Community law.20 However, at the same time, the Community was interested in conducting the adaptation in a way which would ensure that from then on the application of Community law would be uniform throughout the Community, as it was to be feared that otherwise all Member States could employ a divergence from Community law regulations - not intended nor backed up by Community law - to give national interests priority over the Community's interest in uniform application of the law.
At the subsequent accessions (second round: Greece in 1981; third round: Spain and Portugal in 1986) one cannot fail to notice that especially the transitional arrangements as to free movements of workers were, first of all, made in order to protect the old Member States.21 A special differentiation was agreed upon by extending the transitional period in favor of only one Member State, Luxembourg, thus conceding a kind of protection that was reaching beyond the arrangements made for the benefit of the other Member States. At the same time, however, it was argued that the restriction of the free movement of workers would help protect the interests of the new Member States. It was pointed out that, through migration of workers who usually possess above average qualifications, already existing regional problems within the accessing states would be worsened by a brain drain. In addition - taking into account the relatively high rate of unemployment in the old Member States - possibly complicated situations for the migrating workers would be created - 22 which seems to be a rather cynical argument, as it should justify the prohibition of migration on the pretext of knowing best under what circumstances an individual should take the decision to migrate or to stay in his country.
b) The temporary character of all transition measures was put into practice by limiting them to a certain period of time.23 Certain substantial conditions were, however, never part of the created exception. The usual approach to regulating transitional measures, therefore, provided an exemption from applying Community regulations that was unlimited in material respects but strictly limited as to timing. Deviations from this were only chosen very rarely.
In the case of "difficulties" or "considerable difficulties," protection measures reaching beyond the exemptions made in a particular case were admissible; this relates to the emergency protection clauses in many acts of secondary Community law whose activation always requires Community action.24 Such clauses, therefore, are hardly an exception and cover merely situations which are not imminent at the time of the accession but which are thought problematic in an abstract way.
A further deviation from the strict time limitation shows in the delayed application of the rules about free movement of workers after the accession of Portugal and Spain.25 It should be emphasized that in this case the Commission was explicitly called upon to monitor the transition process and that, in reaction to the results of this monitoring, the Council could correct the transition regulations in place.
c) The length of the transition periods varies according to the difficulties expected after a particular accession. It also differed depending on the economic and legal situation of the accessing states as well as according to special economic constellations in certain sectors, e.g. the labor markets in the old Member States. As shown especially by regulations for the third accession (Iberian enlargement), transition periods of approximately ten years are at present the upper limit.26
d) In very rare cases the changes related to the accession treaties have possessed permanent character as no time limitations were employed. This is, with some exceptions, the case for the fishery sector,27 for the importation of certain goods from Commonwealth nations on the occasion of the first accession28 and, at the third accession, for the refund of contributions to the United Kingdom, where the accession was a mere opportunity to regulate this unsolved question of British obligations to pay contributions to the Community.
15 See Granell, Les périodes transitoires des différents élargissements de la communauté européenne, RMC 1986, p. 95 et seq. More detailed Lopian, Übergangsrégime für Mitgliedstaaten der Europäischen Gemeinschaften (1994), p. 57 et seq.
16 No. 13 of the Communiqué, to be found at Nass, Englands Aufbruch nach Europa (1971), pp. 99, 102.
17 Herein one can see a ruling principle for the accession treaty, see Lopian, Übergangsrégime für Mitgliedstaaten (footnote 15), p. 71 et seq.
18 This is shown especially clearly if one compares the expansion of the Communities to the north as compared to that to the south.
19 For an overview hereto see Becker, EU-Erweiterung und differenzierte Integration - zu beitrittsbedingten Übergangsregelungen am Beispiel der Arbeitnehmerfreizügigkeit (1999), p. 15 et seq.
20 The accessing states had asked for the according changes in Community law, Nass, Englands Aufbruch (footnote. 16), p. 65.
21 As a "flooding" of the labor markets in those Member States was feared; the new Member States were - at least for a transitional time - not able to relieve their own labor market, see in this context Musto, Spanien und die Europäische Gemeinschaft (1977), p. 162 et seq., and Ritter/Ruppert/Reichart, Wirtschaftsgeographische Aspekte des Beitritts Spaniens zur Europäischen Gemeinschaft, in: Dürr/Kellenbenz/Ritter et al., Spanien auf dem Weg nach Europa? (1985), pp. 83, 146 as to the situation of the Spanish labor market before the accession and the meaning of the expected free movement of workers for the old Member States.
22 See Buck, Griechenland und die Europäische Gemeinschaft (1978), p. 194 et seq., and v. d. Groeben, Die Erweiterung der Europäischen Gemeinschaft durch Beitritt der Länder Griechenland, Spanien und Portugal (1979), p. 57 et seq., according to whom therefore the state monopoly for employment agencies need to be respected and a minimization of possible problems should be reached by a successful industrial, structural and regional policy; similar Fröhlingsdorf, Aspekte des Vertrages über den EG-Beitritt Spaniens, RIW 1986, pp. 100, 103.
23 Also see Lopian, Übergangsrégime für Mitgliedstaaten (footnote 15), p. 78 et seq. who differentiates between pure time-related transition regulations and substantive measures (step-by-step transition, two-phase régime, other measures).
24 As opposed to those emergency clauses which justify action by the Member State without Community authorization but under the control of the ECJ, see Schweitzer/Hummer, Europarecht, 5th ed. (1996), no. 1012.
25 For the possibility of a prolongation of the estimated time-limits see Lopian, Übergangsrégime für Mitgliedstaaten (footnote 15), p. 80 et seq.
26 Glaesner, Die Süderweiterung der Europäischen Gemeinschaft (1985), p. 39, calls the time limits proposed at the third expansion - between seven and thirteen years - "relatively long". For the expansion to the north see also see Much, Rechtliche Grundsatzfragen zur Erweiterung der Europäischen Gemeinschaften, EuR 1972, p. 324, 339, who calls the range of transition dates "so colorful in detail that one only can generally say that all these transition times will end one time."
27 See Gilsdorf, Am Vorabend des Eintritts Spaniens und Portugals in die EG (1986), p. 24 et seq. who points out that the regulations contained in the accession treaties for Spain and Portugal were restricted time-wise, that however the transition times were chosen in a way that they reached beyond the Community regulations in force at the time of accession. This means at the same time that if new regulations are to be made at Community level after the expiry of transition measures, no special rights have to be respected any longer.
28 See protocol no. 18 about imports of butter and cheese from New Zealand into the United Kingdom ( OJ L73/173) which however explicitly stated that the respective exceptions should only be of a transitional nature.